Continuous mixed venous oximetry in critically ill surgical patients. 'High-tech' cost-effectiveness.

Mixed venous oxygen saturation (Svo2) provides a measure of cardiorespiratory ability to meet the body's needs for oxygen. The Svo2 was measured continuously in 20 critically ill surgical patients using a pulmonary-artery oximetry system. The accuracy of the technique was validated by comparing initial continuous Svo2 to the laboratory determination of Svo2. Oximetry was used to guide therapeutic decisions regarding fluid, inotropic agents, vasodilators and ventilator setting and was useful in ten cases. Sepsis developed in nine patients; this severely limited the usefulness of the technique. With clinical decision making based on oximetry, there was a savings per catheter of 2.65 cardiac output determinations and 5.9 venous blood gas determinations, resulting in a net savings per catheter of +75.